To start, when I first got the car I drove very normally. Occasionally hitting the gas a bit harder, but generally driving very "average" (not leaving anyone behind me from lights but not slowing anyone down, either). After 2-3 months (probably around 10k miles) I started hitting the gas a bit harder, but still nothing crazy. I'd gun it from a light 2-3 times per month, but otherwise no racing or anything of the sort. My average MPG in the first 6 months hovered around 31-32. I'd say approximately 75% of my driving is highway (15 min drive to work, all highway and not much traffic since I live in the city and work 20 min west of it).

Here I am 18 months later (bit more, but it started happening around there) and my average MPG is now below 29. The worst part? I now *baby* the gas far more than I did before. I still don't get left behind at lights, but I rarely pass people unless I don't have to speed up, and I very very rarely put my foot anywhere near the floor. I drive very conservatively and my MPG is 28-29 with pretty much every fill-up.

It all started after that last transmission update. It screwed up the way my car drives, and it also lowered my MPG (I'm seeing a consistent 10% drop from previously). I asked them about it at the dealership and they took it for a test drive. He got back and he said "the car reads 34MPG after we reset it and drove it for 5 minutes". I got in and it said "30.4MPG", because they took it for a 5 min stint on the highway and reset it just after getting up to speed.

Anyone else having reduced MPG problems? I'm lucky to get around 340 miles on a full tank of gas, whereas before I was close to 400. And no, it's not the gauge. I filled up with 11.84 gallons today after 329 miles...and I'd say at least 80% of that was highway steady cruising at 68mph (according to the cruise control speedo).

340 miles in town on a full tank? that is about what i am getting showing an average of 29 mpg. Granted when i full up (light comes on ~47 miles till empty) i only put in 9.75 gallons. I don't think i ever put in more than that much in the car.

But 80% highway does seems a bit low. They switch to winter gas there yet?

To start, when I first got the car I drove very normally. Occasionally hitting the gas a bit harder, but generally driving very "average" (not leaving anyone behind me from lights but not slowing anyone down, either). After 2-3 months (probably around 10k miles) I started hitting the gas a bit harder, but still nothing crazy. I'd gun it from a light 2-3 times per month, but otherwise no racing or anything of the sort. My average MPG in the first 6 months hovered around 31-32. I'd say approximately 75% of my driving is highway (15 min drive to work, all highway and not much traffic since I live in the city and work 20 min west of it).

Here I am 18 months later (bit more, but it started happening around there) and my average MPG is now below 29. The worst part? I now *baby* the gas far more than I did before. I still don't get left behind at lights, but I rarely pass people unless I don't have to speed up, and I very very rarely put my foot anywhere near the floor. I drive very conservatively and my MPG is 28-29 with pretty much every fill-up.

It all started after that last transmission update. It screwed up the way my car drives, and it also lowered my MPG (I'm seeing a consistent 10% drop from previously). I asked them about it at the dealership and they took it for a test drive. He got back and he said "the car reads 34MPG after we reset it and drove it for 5 minutes". I got in and it said "30.4MPG", because they took it for a 5 min stint on the highway and reset it just after getting up to speed.

Anyone else having reduced MPG problems? I'm lucky to get around 340 miles on a full tank of gas, whereas before I was close to 400. And no, it's not the gauge. I filled up with 11.84 gallons today after 329 miles...and I'd say at least 80% of that was highway steady cruising at 68mph (according to the cruise control speedo).

I'm wondering what the adaptive effect is here and maybe if you disconnected the battery and started the learning thing over again that might help.

OTH, this is now the winter season and the fuel blend tends to lower mileage. Also, idling to warm it up eats gas as does the richer fuel mixture while it's warming. Fianlly, the air density is higher as it gets colder and that lower mileage, it tends to improve max power but at the cost of lower mileage.

I'm wondering what the adaptive effect is here and maybe if you disconnected the battery and started the learning thing over again that might help.

OTH, this is now the winter season and the fuel blend tends to lower mileage. Also, idling to warm it up eats gas as does the richer fuel mixture while it's warming. Fianlly, the air density is higher as it gets colder and that lower mileage, it tends to improve max power but at the cost of lower mileage.

Brian

I understand and agree with all of that, but I don't think it's even dropped below freezing here yet. Cleveland is usually pretty cold this time of year already, but today it was high 50s, as it has been pretty much all week (I think Monday it was high 30s, but that's it).

Up until the past 2 weeks, it's been 50-60 every day since summer (with very few exceptions). Winter fuel is most likely out now, but this problem has been going on since mid-summer. I've had it at the dealership for other things twice and mentioned it, and both times they said it's perfectly acceptable.

I'm seeing the same thing. I am thinking it's a combination of colder temps, winter fuel blend and driving on roads with standing water all of the time. I was getting around 31ish and now I'm in the 28 range.

My daily driving consists of 42 total miles, 36 of which is 75mph I-95 traffic in Northern Virginia. I am averaging 27mpg in my 2012 Titanium on the same driving I used to get 32 mpg in a 2008 Focus SES wth 92,000 miles. This is very disappointing fuel economy for a small hatchback. You can get that kind of performance in some full size cars and mid size SUVs. I understand I am not going to get the advertised 38 mpg but for highway driving over the past 3 months where the ambient temperature averages in the 60s. How bad is 27mpg? I used to own an 82 Buick Lesabre full size car with a 5 liter V-8 engine which got 27mpg in mixed driving! Something is not right here.

Have you checked the tire pressure yet? Every month you should be checking the tire pressure to make sure it is set correctly.

I would think the TPMS would alert you long before it got low enough to affect fuel economy.

My gut feeling is that the 12B37 update does not negatively affect fuel economy in a significant way. I got the update a few months ago and driveability worsened, the 6th gear shift point got moved up, but I never saw a decrease in mpg. I even had some clutch slippage issues (uneven accel. / speed and rpms not linearly related while accelerating) which led my dealer to replace the clutches a few hundred miles. But despite the clutch problems I still noticed no significant decrease in economy.

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